A regex for version number parsing

Question

Hi,

I have a version number of the following form:

version.release.modification

where version, release and modification are either a set of digits or the '*' wildcard character. Additionally, any of these numbers (and any preceding .) may be missing.

So the following are valid and parse as:

1.23.456 = version 1, release 23, modification 456
1.23     = version 1, release 23, any modification
1.23.*   = version 1, release 23, any modification
1.*      = version 1, any release, any modification
1        = version 1, any release, any modification
*        = any version, any release, any modification

But these are not valid:

*.12
*123.1
12*
12.*.34

Can anyone provide me a not-too-complex regex to validate and retrieve the release, version and modification numbers?

Many thanks!

---

Thanks for all the responses! This is ace :)

Based on OneByOne's answer (which looked the simplest to me), I added some non-capturing groups (the '(?:' parts - thanks to VonC for introducing me to non-capturing groups!), so the groups that do capture only contain the digits or * character.

^(?:(\d+)\.)?(?:(\d+)\.)?(\*|\d+)$

Many thanks to everyone!

Answer 1

This might work:

^(\*|\d+(\.\d+){0,2}(\.\*)?)$

At the top level, "*" is a special case of a valid version number. Otherwise, it starts with a number. Then there are zero, one, or two ".nn" sequences, followed by an optional ".*". This regex would accept 1.2.3.* which may or may not be permitted in your application.

The code for retrieving the matched sequences, especially the (\.\d+){0,2} part, will depend on your particular regex library.

Answer 2

Use regex and now you have two problems. I would split the thing on dots ("."), then make sure that each part is either a wildcard or set of digits (regex is perfect now). If the thing is valid, you just return correct chunk of the split.

Answer 3

I'd express the format as:

"1-3 dot-separated components, each numeric except that the last one may be *"

As a regexp, that's:

^(\d+\.)?(\d+\.)?(\*|\d+)$

[Edit to add: this solution is a concise way to validate, but it has been pointed out that extracting the values requires extra work. It's a matter of taste whether to deal with this by complicating the regexp, or by processing the matched groups.

In my solution, the groups capture the "." characters. This can be dealt with using non-capturing groups as in ajborley's answer.

Also, the rightmost group will capture the last component, even if there are fewer than three components, and so for example a two-component input results in the first and last groups capturing and the middle one undefined. I think this can be dealt with by non-greedy groups where supported.

Perl code to deal with both issues after the regexp could be something like this:

@version = ();
@groups = ($1, $2, $3);
foreach (@groups) {
    next if !defined;
    s/\.//;
    push @version, $_;
}
($major, $minor, $mod) = (@version, "*", "*");

Which isn't really any shorter than splitting on "." ]

Answer 4

Keep in mind regexp are greedy, so if you are just searching within the version number string and not within a bigger text, use ^ and $ to mark start and end of your string. The regexp from Greg seems to work fine (just gave it a quick try in my editor), but depending on your library/language the first part can still match the "*" within the wrong version numbers. Maybe I am missing something, as I haven't used Regexp for a year or so.

This should make sure you can only find correct version numbers:

^(\*|\d+(\.\d+)*(\.\*)?)$

edit: actually greg added them already and even improved his solution, I am too slow :)

Answer 5

I tend to agree with split suggestion.

Ive created a "tester" for your problem in perl

#!/usr/bin/perl -w


@strings = ( "1.2.3", "1.2.*", "1.*","*" );

%regexp = ( svrist => qr/(?:(\d+)\.(\d+)\.(\d+)|(\d+)\.(\d+)|(\d+))?(?:\.\*)?/,
            onebyone => qr/^(\d+\.)?(\d+\.)?(\*|\d+)$/,
            greg => qr/^(\*|\d+(\.\d+){0,2}(\.\*)?)$/,
            vonc => qr/^((?:\d+(?!\.\*)\.)+)(\d+)?(\.\*)?$|^(\d+)\.\*$|^(\*|\d+)$/,
            ajb => qr/^(?:(\d+)\.)?(?:(\d+)\.)?(\*|\d+)$/,
            jrudolph => qr/^(((\d+)\.)?(\d+)\.)?(\d+|\*)$/
          );

  foreach my $r (keys %regexp){
    my $reg = $regexp{$r};
    print "Using $r regexp\n";
foreach my $s (@strings){
  print "$s : ";

    if ($s =~m/$reg/){
    my ($main, $maj, $min,$rev,$ex1,$ex2,$ex3) = ("any","any","any","any","any","any","any");
    $main = $1 if ($1 && $1 ne "*") ;
    $maj = $2 if ($2 && $2 ne "*") ;
    $min = $3 if ($3 && $3 ne "*") ;
    $rev = $4 if ($4 && $4 ne "*") ;
    $ex1 = $5 if ($5 && $5 ne "*") ;
    $ex2 = $6 if ($6 && $6 ne "*") ;
    $ex3 = $7 if ($7 && $7 ne "*") ;
    print "$main $maj $min $rev $ex1 $ex2 $ex3\n";

  }else{
  print " nomatch\n";
  }
  }
print "------------------------\n";
}

Current output:

> perl regex.pl
Using onebyone regexp
1.2.3 : 1. 2. 3 any any any any
1.2.* : 1. 2. any any any any any
1.* : 1. any any any any any any
* : any any any any any any any
------------------------
Using svrist regexp
1.2.3 : 1 2 3 any any any any
1.2.* : any any any 1 2 any any
1.* : any any any any any 1 any
* : any any any any any any any
------------------------
Using vonc regexp
1.2.3 : 1.2. 3 any any any any any
1.2.* : 1. 2 .* any any any any
1.* : any any any 1 any any any
* : any any any any any any any
------------------------
Using ajb regexp
1.2.3 : 1 2 3 any any any any
1.2.* : 1 2 any any any any any
1.* : 1 any any any any any any
* : any any any any any any any
------------------------
Using jrudolph regexp
1.2.3 : 1.2. 1. 1 2 3 any any
1.2.* : 1.2. 1. 1 2 any any any
1.* : 1. any any 1 any any any
* : any any any any any any any
------------------------
Using greg regexp
1.2.3 : 1.2.3 .3 any any any any any
1.2.* : 1.2.* .2 .* any any any any
1.* : 1.* any .* any any any any
* : any any any any any any any
------------------------

Answer 6

(?ms)^((?:\d+(?!\.\*)\.)+)(\d+)?(\.\*)?$|^(\d+)\.\*$|^(\*|\d+)$

Does exactly match your 6 first examples, and rejects the 4 others

• group 1: major or major.minor or '*'
• group 2 if exists: minor or *
• group 3 if exists: *

You can remove '(?ms)'
I used it to indicate to this regexp to be applied on multi-lines through QuickRex

Answer 7

Don't know what platform you're on but in .NET there's the System.Version class that will parse "n.n.n.n" version numbers for you.

Answer 8

This matches 1.2.3.* too

^(*|\d+(.\d+){0,2}(.*)?)$

I would propose the less elegant:

(*|\d+(.\d+)?(.*)?)|\d+.\d+.\d+)

Answer 9

Thanks for all the responses! This is ace :)

Based on OneByOne's answer (which looked the simplest to me), I added some non-capturing groups (the '(?:' parts - thanks to VonC for introducing me to non-capturing groups!), so the groups that do capture only contain the digits or * character.

^(?:(\d+)\.)?(?:(\d+)\.)?(\*|\d+)$

Many thanks everyone!

Answer 10

Another try:

^(((\d+)\.)?(\d+)\.)?(\d+|\*)$

This gives the three parts in groups 4,5,6 BUT: They are aligned to the right. So the first non-null one of 4,5 or 6 gives the version field.

• 1.2.3 gives 1,2,3
• 1.2.* gives 1,2,*
• 1.2 gives null,1,2
• *** gives null,null,*
• 1.* gives null,1,*

Answer 11

It seems pretty hard to have a regex that does exactly what you want (i.e. accept only the cases that you need and reject all others and return some groups for the three components). I've give it a try and come up with this:

^(\*|(\d+(\.(\d+(\.(\d+|\*))?|\*))?))$

IMO (I've not tested extensively) this should work fine as a validator for the input, but the problem is that this regex doesn't offer a way of retrieving the components. For that you still have to do a split on period.

This solution is not all-in-one, but most times in programming it doesn't need to. Of course this depends on other restrictions that you might have in your code.

Answer 12

^(?:(\d+)\.)?(?:(\d+)\.)?(\*|\d+)$

Perhaps a more concise one could be :

^(?:(\d+)\.){0,2}(\*|\d+)$

This can then be enhanced to 1.2.3.4.5.* or restricted exactly to X.Y.Z using * or {2} instead of {0,2}

Answer 13

This should work for what you stipulated. It hinges on the wild card position and is a nested regex:

^((\*)|([0-9]+(\.((\*)|([0-9]+(\.((\*)|([0-9]+)))?)))?))$

http://imgur.com/3E492.png